Reliability and cost considerations have caused aircraft designers to consider the use of variable-frequency electrical distribution systems. The majority of AC loads on an aircraft can accommodate various source frequencies, and therefore can operate with either fixed or variable drive frequencies. AC induction motors are very desirable for aircraft use, as they are rugged, reliable, and inexpensive. AC induction motors, however, are designed for constant volts-per-Hertz drive, for example 120 VAC at 400 Hz. When operated at frequencies other than the design frequency, such motors convert power inefficiently, and draw increased drive current. Known systems drive such AC induction motors directly from the variable-speed AC source, with the result that the inefficient power conversion reduces the useful torque, so the size of the rotor must be increased in order to maintain the power conversion. Thus, the motors must be larger and concomitantly heavier, and dissipate more heat than is desirable. Improved arrangements for operating AC induction motors from variable-speed sources are desired.